Minosmoney
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Force the 3.5mm jack to output video, not HDMI

Fri Jan 05, 2018 2:30 am

Hello Everyone,
I recently invested in a raspberry pi 3 to make a Lunchbox Laptop from a book I purchased. I setup the Pi with HDMI. Now I need to figure out how to use the 3.5 mm jack to output video. I have a cable for it but I can not figure out how to make a video signal to come out. I think my Pi has the HDMI port set as the default. How can I change this to the 3.5 mm jack? I have looked around on different websites but none of them work!! PLEASE HELP ME I AM NEW AT THIS AND DON'T KNOW HOW TO DO IT!Thank you!! :D

fruitoftheloom
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Re: Force the 3.5mm jack to output video, not HDMI

Fri Jan 05, 2018 9:52 am

Minosmoney wrote:
Fri Jan 05, 2018 2:30 am
Hello Everyone,
I recently invested in a raspberry pi 3 to make a Lunchbox Laptop from a book I purchased. I setup the Pi with HDMI. Now I need to figure out how to use the 3.5 mm jack to output video. I have a cable for it but I can not figure out how to make a video signal to come out. I think my Pi has the HDMI port set as the default. How can I change this to the 3.5 mm jack? I have looked around on different websites but none of them work!! PLEASE HELP ME I AM NEW AT THIS AND DON'T KNOW HOW TO DO IT!Thank you!! :D

The TRRS4 Audio Video Jack is Composite Output and Left & Right Audio, you will need a correctly wired cable, see:

https://www.raspberrypi-spy.co.uk/2014/ ... ideo-jack/


If you have installed standalone Raspbian then it will output composite video if no HDMi Cable is attached, this is default behaviour but is NTSC, you will need to change this if your equipment expects a differing TV Standard, see link at bottom of reply.


If you have used NoobS to install Raspbian, then the readme explains how to default to Composite Output:

https://github.com/raspberrypi/noobs/bl ... /README.md


Last but not least Composite Output is very low quality and SDTV Mode has few options:

https://www.raspberrypi.org/documentati ... t/video.md
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itimpi
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Re: Force the 3.5mm jack to output video, not HDMI

Fri Jan 05, 2018 8:13 pm

Minosmoney wrote:
Fri Jan 05, 2018 2:30 am
Hello Everyone,
I recently invested in a raspberry pi 3 to make a Lunchbox Laptop from a book I purchased. I setup the Pi with HDMI. Now I need to figure out how to use the 3.5 mm jack to output video. I have a cable for it but I can not figure out how to make a video signal to come out. I think my Pi has the HDMI port set as the default. How can I change this to the 3.5 mm jack? I have looked around on different websites but none of them work!! PLEASE HELP ME I AM NEW AT THIS AND DON'T KNOW HOW TO DO IT!Thank you!! :D
By default the Composite video is automatically activated if no HDMI device is detected. You do need a correctly wired cable (there are several differently wired variants commonly sold) and the quality is not very good so you need to be aware of that. Also it is possible to have a the RPi3 forced or always use HDMI if you have manually edited the config.txt file on the boot partition but you should be aware of it if you have done that.

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mahjongg
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Re: Force the 3.5mm jack to output video, not HDMI

Sun Jan 07, 2018 2:07 pm

itimpi wrote:
Fri Jan 05, 2018 8:13 pm
By default the Composite video is automatically activated if no HDMI device is detected.
this is not true if you install using NOOBS, when using NOOBS it always defaults to HDMI, and you have to switch to PAL or NTSC by pressing 3 or 4 while in NOOBS, or 1 for HDMI or 2 for safe HDMI, the setting is then made permanent in config.txt.

therefore, for a system that uses composite, I would advice using an image writer, so that at least you get some video, even though it will be NTSC by default, (you can change that to the correct video format used in your country by editing config.txt, which should be possible even with a PAL TV)

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davidcoton
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Re: Force the 3.5mm jack to output video, not HDMI

Sun Jan 07, 2018 3:18 pm

mahjongg wrote: it always defaults to HDMI, and you have to switch to PAL or NTSC by pressing 2 or 3 while in NOOBS, or 1 for HDMI or 2 for safe HDMI,
Close, but not quite:
github wrote:By default, NOOBS will output over HDMI at your display's preferred resolution, even if no HDMI display is connected. If you do not see any output on your HDMI display or are using the composite output, press 1, 2, 3 or 4 on your keyboard to select HDMI preferred mode, HDMI safe mode, composite PAL mode or composite NTSC mode respectively.
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